1. Field of the Invention
The present invention relates to a process of manufacturing carrot juice having a high-quality and stable characteristic free from occurrence of cohesion.
2. Related art statement
Generally, a conventional manufacturing process of carrot juice comprises: heating (blanching) carrot in boiling water to deactivate enzyme, and thereafter crushing and grinding it to squeeze juice. However, this process has a problem that the rate of squeeze is low, a color tone of squeezed juice is bad, blanching requires a long period of time to give the squeezed juice heated smell, and its taste is also bad. Japanese Patent Application Laid-Open No. HEI 6-217744 discloses a manufacturing process comprising: first, adding vitamin C and/or citric acid component while crushing or cutting carrot, heating (blanching) the resultant crushed material to a product temperature of 80 to 90xc2x0 C. to deactivate enzyme, then squeezing juice by a biaxial rotary type extruder to obtain the juice.
When blanching is carried out after the carrot has been crushed, as in the invention disclosed in the above-described Japanese Patent Application Laid-Open No. HEI 6-217744, the heated smell is removed, but fishiness is so severe that the juice is hard to take.
From the foregoing, if the above-described invention is merely changed to carry out crushing after blanching, where blanching takes place so that a product temperature reaches 80 to 90xc2x0 C., there poses a problem that the heated smell is given to the squeezed juice, and when the product temperature is lowered in order to avoid the heated smell, cohesion occurs, lowering the quality on the contrary.
Further, it has been found that when blanching is carried out in boiling water to allow the product temperature reach 80 to 90xc2x0 C., the rate of squeeze lowers, and the taste also deteriorates.
In view of the foregoing, it is an object of the present invention to elucidate the cause of cohesion in the manufacturing of carrot juice, and to provide, in a manufacturing process comprising crushing after blanching carrot, a manufacturing process of carrot juice capable of obtaining, with high yield, carrot juice being less fishy and free from occurrence of cohesion, and having a high-quality and stable characteristic.
A manufacturing process of carrot juice according to the present invention is characterized by comprising: peeling raw carrot, completely deactivating pectin esterase activity of carrot without passage of one day or more in the peeled state, carrying out enzyme deactivation processing so that the residual rate of pectinase activity is less than 60%, and thereafter crushing and squeezing it.
That is to say, in the present invention, it is necessary to carry out enzyme deactivation processing without passage of one day or more, preferably, 12 hours or more after peeling of the peeled raw carrot. The reason why is that when one day or more passes in the peeled state, it is difficult to prevent an occurrence of cohesion even if sufficient blanching takes place till the product temperature reaches, for example, 90xc2x0 C.
The enzyme deactivation processing according to the present invention is to completely deactivate pectin esterase activity of carrot and to make the residual rate of pectinase activity less than 60%. There is the possibility to generate cohesion if the pectin esterase activity is not completely deactivated or the residual rate of pectinase activity is 60% or more.
As a first example of such an enzyme deactivation processing as described, there can be mentioned a process of blanching carrot till an internal temperature reaches 70 to 80xc2x0 C. in water at 70 to 80xc2x0 C. By this process, the pectin esterase activity of carrot can be completely deactivated, and the residual rate of pectinase activity can be made less than 60%. In such as process as described, when a water temperature for blanching is lower than 70xc2x0 C., cohesion occurs due to the function of pectin cracked enzyme, and at a temperature higher than 80xc2x0 C., the yield reduces, and the heated smell results.
As a second example, there can be mentioned a process of blanching carrot till an internal temperature reaches 60 to 70xc2x0 C. in a 0.02M to 0.05M citric acid solution at 60 to 70xc2x0 C. Even by this process, not only the pectin esterase activity can be completely deactivated, and the residual rate of pectinase activity can be made less than 60% but also a water temperature for blanching can be further lowered, whereby it is possible to further positively prevent adhesion of the heated smell, and in addition, the yield can be further enhanced.
As a third example, there can be mentioned a processing of carrot by super-critical carbonic acid gas, for example, a processing by a microbubble SCxe2x80x94CO2 process. Even by this process, not only the pectin esterase activity can be completely deactivated, and the residual rate of pectinase activity can be made less than 60% but also a water temperature for blanching can be further lowered.
As a fourth example, there can be mentioned a process comprising a combination of the above-described first or second blanching process and the above-described third super-critical carbonic acid gas processing process. According to such a combined process as described, the pectin esterase activity can be completely deactivated, and the residual rate of pectinase activity can be made less than 60% and it is possible to prevent adhesion of the heated smell.